High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect
High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect
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DOI：
10.3390/s20041117
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发表时间：
2020-02-01
期刊：
影响因子：
3.9
通讯作者：
Xu, Dacheng
中科院分区：
文献类型：
--
作者：
Gao, Lu;Chen, Fang;Xu, Dacheng
提出了一种基于超灵敏隧道磁阻（TMR）传感器的高精度加速度测量系统。设计了一种力-磁-电耦合结构，将输入加速度转换为TMR传感器周围磁场的变化。在这种结构中，微悬臂梁与其尖端上的磁场源集成在一起。在加速度下，悬臂的机械位移引起TMR传感器感测到的空间磁场的变化。TMR传感器采用惠斯通电桥结构，以提高灵敏度。同时，为进一步提高加速度测量精度，设计了一种低噪声差分电路。实验结果表明，该微系统实现了19 μ g/根Hz的测量分辨率在1 Hz，191 mV/g的比例因子的范围内+/-2 g，和38 μ g的偏置不稳定性（Allan方差）。对系统的噪声源进行了深入的研究，结果表明低频1/f噪声是系统的主要噪声源。我们建议使用高频调制技术来有效抑制1/f噪声。测量结果表明，1/f噪声被抑制约8.6倍，在1 Hz和建议的系统分辨率可以提高到2.2 μ g/根Hz理论上与这种高频调制技术。
A high-precision acceleration measurement system based on an ultra-sensitive tunnel magneto-resistance (TMR) sensor is presented in this paper. A "force-magnetic-electric" coupling structure that converts an input acceleration into a change in magnetic field around the TMR sensor is designed. In such a structure, a micro-cantilever is integrated with a magnetic field source on its tip. Under an acceleration, the mechanical displacement of the cantilever causes a change in the spatial magnetic field sensed by the TMR sensor. The TMR sensor is constructed with a Wheatstone bridge structure to achieve an enhanced sensitivity. Meanwhile, a low-noise differential circuit is developed for the proposed system to further improve the precision of the measured acceleration. The experimental results show that the micro-system achieves a measurement resolution of 19 mu g/root Hz at 1 Hz, a scale factor of 191 mV/g within a range of +/- 2 g, and a bias instability of 38 mu g (Allan variance). The noise sources of the proposed system are thoroughly investigated, which shows that low-frequency 1/f noise is the dominant noise source. We propose to use a high-frequency modulation technique to suppress the 1/f noise effectively. Measurement results show that the 1/f noise is suppressed about 8.6-fold at 1 Hz and the proposed system resolution can be improved to 2.2 mu g/root Hz theoretically with this high-frequency modulation technique.